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Nauru99 R/V Mirai DBS Wind Profiler Composite Day

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NCAR operated a DBS wind profiler radar on board the R/V Mirai during the Nauru99 field campaign. The above image is an average, or "composite", day formed by taking the median, for each hour of the day, of the hourly measurements made by the profiler during 20 - 30 June. During this time the Mirai was stationed near a NOAA ATLAS Buoy (165E 0S) about 200 km WNW of the island of Nauru in the central Pacific.

The main features that can be discerned are :
• There are strong echoes between 500 - 1200 metres altitude that do not vary much with time of day (top panel). These echoes probably correspond to the top of the boundary layer.
• There are predominantly easterly winds, which are stronger with increasing altitude (middle panel). During the day (say between 6 am and 6 pm local time), these winds are stronger than at night, particularly at around 2 km altitude.
• The north-south component of the winds are weak (bottom panel), being slightly southerly most of the day between 1 - 2 km, and perhaps being slightly southerly at lower levels during the early morning hours.